Glucagon Basics and Regulation of Glucagon Secretion

00:00 Glucagon.

00:01 Here we need to talk about where it's produced.

00:05 Glucagon is produced in the islet cells and specifically the alpha component.

00:11 We also think about there are few other places in which glucagon like substances are produced.

00:17 And that is in the GI system.

00:19 This procudes glucagon like peptide.

00:22 But the primary glucagon is from the pancreas.

00:27 Now, we have to think about how long is glucagon in the circulation.

00:33 About 80% of it is cleared after the first path.

00:38 And you remember what the first path is, this is as you go through the circulartory system one time, the liver is going to clear about 80%.

00:48 That means that the half life of glucagon is only 5 to 10 minutes.

00:54 So it's not going to be around for too long period of time.

00:58 It's good things to keep in mind as you're talking about where it's produced.

01:03 How long it's going to stay in circulation.

01:06 The things that control the secretion of glucagon are decrease in blood glucose.

01:12 So blood glucose level is low, it's going to be a stimulus to make more glucagon.

01:20 If there is an increase in amino acid concentration, specially, arginine and lysine, as well as the sympathetic nervous system is engaged.

01:30 The fight or flight response stimulates glucagon release.

01:34 We also have stress and excercise that both being potent stimuli for glucagon.

01:42 A few things inhibit glucagon secretion.

01:45 Insulin being the primary one.

01:47 So if insulin levels are high it's going to suppress glucagon release.

01:53 The last item is the somatostatin is also in the pancreatic islet cells.

01:58 And there in fact potentially decrease it's secretion right from the islet.

02:11 Glucose, amino acids, fatty acids, and even secretin and cholecystokinin can also be involved in this process of inhibiting glucagon secretion.

02:22 These will be associated with increases with a meal.